Seo Ji Sung (Song Ha Yoon) is programmer of smart home appliances. A new smart refrigerator she is working on inadvertently has a lost super-advanced AI chip belonging to the National Intelligence Service installed. Instead of a program that rates the freshness of vegetables, it seems to be able to detect men with bad characters. First it saves the women around her from troubled relationships, then it flags her seemly-perfect fiancé as a bad apple. She gets involved with firefighter Jung Koon Hee (Lee Joon Young).